For the purpose of preparing aerated beverages on a small scale, for example in the home, apparatus are known by means of which carbon dioxide can be supplied to water in a bottle, the water then being flavoured with a flavouring substance. In the preparation of such beverages, it is necessary to first fill a bottle with water up to a given level, and then to hold the bottle firmly gripped in the apparatus while supplying carbon dioxide to the water. The bottle is then removed from the apparatus and the flavouring substances added. The beverage is then ready to be poured into a drinking glass or the like.
In addition to being relatively complicated, since among other things it requires the use of a separate bottle whose form and size are adapted to the apparatus in question, the aforedescribed procedure for preparing aerated beverages is also encumbered with other problems and safety risks. Among other things, it is difficult to obtain an accurate seal when using standard bottles, since these bottles can vary greatly in height. In addition, risks are involved when subjecting return bottles to pressure, since in addition to uneven manufacturing quality the bottles may have been damaged during previous use or transportation. Further, in the case of known apparatus the bottle can be pressurized without having been filled with liquid, which presents a risk of serious injury should the bottle explode. It is also possible with known apparatus to overfill the bottle with liquid, rendering it impossible to supply sufficient carbon dioxide to the liquid. In order to aerate a liquid effectively in a container, it is necessary to provide above the surface of the liquid a space in which the gas can be compressed.
It has also been proposed to introduce carbon dioxide into a liquid enclosed in a container fixed in an apparatus, and to pour the aerated liquid directly from the container into a glass. The use of this container is also relatively complicated, however, and in some respects the arrangement is unsafe. Thus, it is also possible with this arrangement to pressurize the container when it is empty. Also, it has been possible to pour liquid from the container while the container still is under high pressure.